Theta Defensin

Theta-defensin is a cyclopeptide that can prevent viruses from entering cells. It is thought to have anti-HIV activity.

It was first found in macaques. Although the human genome contains the genes to encode theta-defensin, there is a premature stop codon that prevents the human genome from transcribing it. In software engineering, we would refer to the sitution where some code used to work, but now doesn’t for small esoteric reasons, as “bitrot.” In biology, we call these genes “pseudogenes.” It turns out that a researcher, Alexander Cole, was able to cause humans to produce theta-defensin, with a drug that caused the transcription pipelines to ignore the stop codon.

The cyclopeptide itself is formed by concatenating two linear peptides:

By Thomas Shafee - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=35375915